1. Field of the Invention
The present invention relates to image pick-up technology, and more particularly, to a barrel-based white balance filter, which comprises an opaque barrel, and a white balance component axially adjustably mounted in the opaque barrel. The invention uses the opaque barrel to isolate the color temperature beyond the viewing scene, and allows adjustment of the proportion of the amount of the color temperature of the main light source using the light transmissive property of the white balance filter of the white balance unit, achieving the effect of increasing or reducing the average color temperature like the functioning of the eyelid to adjust the intraocular pressure subject to the brightness of the main light source so that the color is closer to the human eye visual sense and personal preferences.
2. Description of the Related Art
White balance filter plate (7) or white balance lens cap (6) with a filter (61) may be used with a camera (2). During application, as illustrated in FIGS. 13, 14 and 15, the white balance filter plate (7) or white balance lens cap (6) is attached to the camera lens (21) of the camera (2), and then the shutter is pressed to run the manual white balance mode, getting the average white balance value of the viewing scene. This average white balance value is used as a single color temperature for photographing.
Red, blue and green are three most basic colors that can be combined to make a useful range of colors. For human applications, these three primary colors are usually used, since human color vision is trichromatic. Only the values of these three primary colors are equal to each other, R=B=G, the correct white can be presented in the human vision. If white is accurately corrected or displayed, all other colors of photos or videos can be presented correctly in the human vision.
The manual white balance mode of a camera is to accurately measure the average color temperature of the viewing scene for use as a color temperature reference value so that accurate colors can be exhibited in the artworks, greatly reducing further software color temperature revising works. Because the colors of photos or videos having an incorrect color temperature are inconsistent with the scene of the photography site, the high-precision human visual system can easily senses the differences, all camera artworks in incorrect color are failed artworks to all people.
Each single picture of photos, videos, or live videos is presented in the human vision based on a single color temperature. The human vision can instantly senses any change or error of the color temperature. Therefore, getting the color temperature value of the scene is one of the most important works of the success of the artwork.
However, attaching a conventional white balance filter plate (7) or white balance lens cap (6) for a manual white balance operation cannot accurately get the color temperature and colors of the photography scene due to poor overall design of the white balance filter plate (7) or white balance lens cap (6). When facing the white balance filter plate (7) or white balance lens cap (6) toward the viewing scene, all the surrounding lights and colors non-selectively fall upon the filter to make an incorrect average color temperature value.
Actually, every color of a physical object has its particular color temperature value under every light source. When changing the shooting direction of the camera during photographing, the composition of the photograph range and color ratio are relatively changed, and the average color temperature value of each picture is also changed. So, only focus on the area of the scene to be photographed can get the most precise average white balance value.
In an outdoor operation, the scene taken by the camera (2) depends upon the view angle and distance of the focus of the camera lens (21). Photographing has its scene range. During application of the white balance filter plate (7) or white balance lens cap (6), unnecessary ambient light beyond the viewed range will be received, such as sunlight, reflected light from the blue sky and white clouds can fall upon the white balance filter plate (7) or white balance lens cap (6) to mix with the incident light from the viewing scene, causing the camera (2) to get an incorrect average color temperature value for photographing. Based on this incorrect average color temperature value, a color shift problem will occur in the photos or videos thus obtained.
During an indoor photography operation, all the outdoor or indoor main light source and other ambient and reflected light rays and colors from all directions will fall upon the white balance filter plate (7) or the filter (61) of the white balance lens cap (6) and enter the color temperature sensing range of the light transmissive structure thereof, giving an incorrect average white balance value to the manual white balance system, resulting in photo color distortion.
In addition to general photography purposes, getting the accurate colors of objects is also very important in scientific research, color management, typography or recording works, for example, to obtain a reference color of an object at different locations or under different light source environments for color calibration to achieve consistency.